In several conditions penetration of solid tissue is indicated in order to treat diseases or correct anomalies in a human body. Some of these conditions will be mentioned here in order to put the here presented innovation into perspective.
The simplest and most used method for penetrating tissue is by means of needles. Punching a needle through solid tissue may connect one compartment of the body with another. The needle will allow a wire or a catheter to be advanced into the next compartment through a central lumen and if necessary followed by a balloon in order to widen the created channel.
Additionally a stent, a net-like metal vessel wall support, may be inserted in order to ensure a persistent open connection. Thus, insertion of a stent is dependent upon an opening being present into which the stent may be advanced before its expansion. However, there is a need for a device and method providing penetration of solid soft tissue of a body where no channel or opening is present, or where an existing passage or channel has been blocked. The penetration is desired to e.g. provide a passage or channel in the solid soft tissue.
Medical conditions where solid tissue penetration and creation of openings or canalization thereof is needed are many and only a few can be mentioned here. Cardiac anomalies are not uncommon, in some instances connections between compartments, e.g. vessels and heart chambers, has to be created by means of surgery or catheter technique.
Ischemic heart disease caused by coronary artery narrowing's or occlusions is one of the most common heart diseases and the most common reason for death in the western world. 15 Millions diagnostic coronary artery angiograms are performed each year in the world for this reason. 12-13 Millions of these investigations reveal artery obstructions requiring an intervention to ensure good blood flow in the coronary arteries. 70-75% of the interventions today are done by catheter technique, percutaneous coronary intervention (PCI). Through the narrowing, known as stenosis, in a coronary artery a guide wire is passed, then the stenosis is dilated by means of a balloon and thereafter a mesh of metal wire formed as a metal mesh tube, known as a stent, is inserted at the treatment site in order to keep the vessel wall from collapsing at the treated site while healing occur.
30% of the coronary angiograms, however, show a chronic total occlusion (CTO) of a coronary artery where it is impossible to pass the occlusion with a needle, a guide wire or a balloon to dilate the occluded spot in the artery. Those patients have only the option of undergoing open heart surgery, being subjected to the coronary artery bypass grafting procedure (CABG).
A PCI usually implies that the patient is discharged from the hospital the same day or the day after and may return to daily activities immediately. A CABG, however means at least one week stay in a hospital and thereafter weeks or months in rehabilitation before returning to normal activities and work. With the newly introduced drug eluting stent technology, the result after PCI and CABG are comparable, however, since the PCI is by far the least invasive it would be preferable in all cases if possible. A demand for methods to pass CTO therefore is imminent, to convert cases from CABG to PCI procedures.
The extensive plaque formation of a chronic total occlusion typically has a fibrous cap surrounding softer plaque material. Such a fibrous cap may present a surface which may be difficult to penetrate with a conventional guidewire. In such instances, the typically flexible distal tip of the guidewire may be unable to cross the lesion, and in order to successfully cross and treat a chronic total occlusion, alternative devices may be required. For example, at a minimum, a stiffer guidewire may be required to traverse the stenosis. Or, an atherectomy device may be required to penetrate the occlusion. Hereinafter, applicants refer to any device intended to penetrate the occlusion, including a guidewire, as a canalizing device or a recanalizing device.
In the event that a canalizing device and/or greater force by the clinician are required in order to create a passageway through a chronic total occlusion, additional precautions must be taken to prevent injury to the vessel wall. Furthermore measures have to be taken as well to prevent debris from the CTO plug to spread with the blood stream, which otherwise might lead to undesired patient damage.
WO0176678A1 discloses an apparatus and a method for the treatment of an occluded lumen. An apparatus for centering of a device which is intended to penetrate a severe occlusion of a body lumen is disclosed. A device is disclosed that provides back support for a recanalizing device during attempts to penetrate an extensive occlusion. A catheter with a substantially central lumen for receiving a guidewire and/or other recanalizing device is provided. An embodiment disclosed also comprises a central lumen for receiving a second catheter for the purpose of conducting an angioplasty procedure and/or delivering a stent. WO0176678A1 discloses a conventional way of penetrating through an occlusion with a wire, inserting a balloon into the channel thus created, inflating the balloon for widening the channel, and inserting a stent for keeping the channel open. Debris is created when traversing the occlusion, which may harm the patient.
US20070032808A1 discloses a system and method for addressing total occlusion in a vascular environment, wherein an apparatus for addressing an occlusion in a vascular environment is provided that includes a wire and a tip coupled to the wire and operable to burrow into an occlusion in a vascular environment. The apparatus also includes a coil section disposed between the wire and the tip and operable to collect debris generated by burrowing of the tip. In US20070032808A1 conventional material removal technique comprising advancing through the hard fibrotic tissue cap is disclosed. Furthermore, debris is created when traversing the occlusion, which is handled by special measures in order to provide patient safety.
However, there is a need for an improved method, system, or device avoiding creating debris when penetrating through a CTO plug.
Since recently two products are available for clinical investigations. LuMend Inc. is offering the Frontrunner™, a catheter based device with inverted pliers at the tip. The tip is advanced after each opening of the pliers jaw. The tissue inside the CTO is forced open a little, letting the canalization device advance a step until the jaws are opened again.
U.S. Pat. No. 6,800,085 assigned to LuMend Inc. discloses this method and apparatus for treating vascular occlusions in detail. An intravascular catheter system for the treatment of occluded blood vessels that includes tissue displacement or hinged expansion members that are movable from a closed to an open position are disclosed in U.S. Pat. No. 6,800,085. The tissue expansion members can stretch apart, tear or otherwise disrupt a vascular occlusion sufficiently to create a pathway that provides a support for the passage or placement of a guidewire or an interventional vascular device across the occlusion or obstruction. However, when the system of U.S. Pat. No. 6,800,085 is used, it does, amongst others, not prevent debris from the occlusion to spread with the blood stream. This is, as mentioned above, not satisfactory with regard to patient safety.
Another system for treating vascular occlusions, the SafeCross offered by Translumina Inc. is also catheter based. The tip of this device is provided with a laser sensor as well as with a high frequency radio wave transmitter (RF), creating heat at the tip. The laser will by means of a computer and its software guide the tip from not penetrating the lumen of the vessel and the RF will heat the tip, burning its way through the tissue.
These prior known methods are expensive, very time consuming, risky and lead to a successful penetration of a CTO in 50% of the cases that could not be penetrated with conventional means like guide wire and balloons. Both methods and devices create debris when penetrating through a CTO plug, which is not desired.
Hence, an improved method and/or device for creating connections, openings, or canals in the body would be advantageous, and in particular such a method and/or device allowing for increased flexibility, cost-effectiveness, and/or patient safety would be advantageous.